The present invention relates to the electrical, electronic, and computer arts, and, more particularly, to methods for forming metal-insulator-metal capacitors.
As the dimensions of semiconductor device shrink, it becomes increasingly more difficult to create capacitor structures that can meet desired performance metrics. Metal oxides such as tantalum pentoxide (Ta2O5) and similar metal oxides are promising candidates as insulators in metal-insulator-metal (MIM) capacitors due to their desirable physical and electrical properties. Tantalum pentoxide (Ta2O5), for example, may have a dielectric constant of about 25, while silicon dioxide (SiO2) may have a dielectric constant of only about 3.9. Nevertheless, significant challenges exist in controlling the resistivity of metal layers in such capacitors, as well as in creating stable interfaces with little or no intermixing between dielectric and metal layers. At the same time, as with any semiconductor fabrication process, there is the desire to keep cost, process complexity, and the number of process steps as low as possible.
There is, as a result, a need for new processing methodologies for forming MIM capacitors.